Asaphus kotlukovi var tumidus Russian Trilobite

Description: A well-inflated example of a medium-eyestalked member of the Asaphidae, this is Asaphus kotlukovi. This particular example is of the variety called tumidus by A.J. Ivantsov. The region in which these trilobites lived was subject to dramatic changes in salinity and turbidity, and the trilobites were able to make rapid (geologically speaking) evolutionary adjustments. These adjustments were thought to be able to allow them to see both predator and prey more easily.

Also see: Russian Trilobites Asaphid Trilobites